How do I turn off "enable hardware acceleration" in Firefox when using Firefox and flash

I have been told that I need to turn off "enable hardware acceleration" in Firefox when using flash to solve my problem of flash freezing when I try to view full screen.
It all works fine............. until I switch to full screen.......then the audio continues and the video freezes.
I'm using a Samsung Tab 2 running Jellybean 4.1, with firefox and the last issue of Flash player
I was told to go to tools in Firefox and select "options", but "options" is not there (just downloads, Add-ons and Apps), so I can't get to the "advanced" tab (I was told I needed to get to), to switch the acceleration off.
How do I do this?
Can anyone help please?

I have been told that I need to turn off "enable hardware acceleration" in Firefox when using flash to solve my problem of flash freezing when I try to view full screen.
It all works fine............. until I switch to full screen.......then the audio continues and the video freezes.
I'm using a Samsung Tab 2 running Jellybean 4.1, with firefox and the last issue of Flash player
I was told to go to tools in Firefox and select "options", but "options" is not there (just downloads, Add-ons and Apps), so I can't get to the "advanced" tab (I was told I needed to get to), to switch the acceleration off.
How do I do this?
Can anyone help please?